Glass-ceramic worktop

ABSTRACT

An item of furniture or appliance includes at least one worktop formed from at least one substrate made of a transparent monolithic glazing material and of area larger than 0.7 m 2 , equipped with a coating so that the substrate equipped with the coating has a haze higher than 15%, a light transmission T L  lower than 60% and an opacity indicator higher than 85. The item of furniture or appliance also includes at least one heating element, at least one light source to light up one or more zones or one or more elements or displays of the substrate, the source being located plumb with the substrate in order to form a display by projection, or under the substrate in order to form a display by transmission through the substrate, and at least one interface for communicating with at least one element of the worktop.

The present invention relates to a worktop, worktable, counter or unitformed from at least one large plate positioned or intended to bepositioned horizontally on one or more supporting elements (carcass of aunit, supporting leg(s)) in order to provide a stable surface intendedfor various uses. In particular, the present invention relates to atable or a unit having a surface or top able to allow, simultaneously orin succession, various activities to be carried out and/or objects to besupported, and in particular allowing food to be heated or cooked inappropriate recipients and other uses to be made thereof.

The materials conventionally used to produce worktops are for examplewood, quartz stone, Cohan®, etc. Moreover in kitchens, in particularprofessional kitchens, it is known to use large typically metal and/orcomposite plate cooktops to cook food. In particular, multilayer platesbased on ceramic layers or components, made of ceramics such asstoneware, metal layers or components, made of metals such as aluminum,and layers or components made of insulating plastics such as Bakelite,are known, these plates generally having a substantial thickness (ofabout 12 mm for example) and being complex to produce.

Similarly, smaller cooktops made of glass-ceramic or toughened glass (inparticular of area generally smaller than 0.4 m², plates of larger areapossibly being more difficult to obtain using conventional processes,and possibly leading to problems with flatness, handling etc.) areknown, in particular for domestic uses, the use of glass-ceramics incooktops having become more widespread in the last few years, especiallybecause of the performance obtained with this material in thisapplication and the attractive appearance of the plates produced.

Various types of glass-ceramic plates are known at the present time,each variant being the result of extensive studies and numerous trialssince it is very difficult to make changes to these plates and/or to theprocess used to obtain them without running the risk of adverselyaffecting the sought-after properties: in order to be able to be used asa cooktop, a glass-ceramic plate must generally have a transmission atwavelengths in the visible domain that is both low enough to allow, whenthey are turned off, the underlying heating elements to be at leastpartially masked, and high enough that, depending on the circumstances(radiant heating, inductive heating, etc.), the user is able, for safetyreasons, to visually detect the heating elements when they are turnedon; such a plate must also have a high transmission at wavelengths inthe infrared domain, especially in the case where the plate is to beassociated with radiant elements. The plates thus designed are intendedto be used exclusively as cooktops and are conventionally neitherintended to receive objects other than the heat-resistant utensils usedin the cooking of food, nor intended to be used for activities otherthan the cooking of food.

The aim of the present invention is to widen the existing range ofhousehold and professional appliances by providing a new type ofinteractive product that has a wider variety of uses.

This aim is achieved by the novel and advantageously interactivearticle, fitting, item of furniture or appliance according to theinvention, this item of furniture/appliance comprising:

-   -   at least one worktop (or counter or worktable) formed from at        least one substrate (in particular a plate or surface or top)        made of (or of (based on) a or essentially consisting of a)        transparent, monolithic (or integrally formed or unitary)        glazing material (in particular having a light transmission        higher than 60%), said substrate advantageously being        essentially flat and of area (length by a width of its largest        face) larger than 0.7 m², equipped with a coating so that the        substrate equipped with the coating has a haze higher than 15%,        a light transmission T_(L) lower than 60% and an opacity        indicator higher than 85;    -   at least one heating element (in particular under the substrate        and hidden by the latter when this heating element is not in        operation/is turned off);    -   at least one light source, in particular intended to light up        (make visible) one or more zones (such as heated zones) or one        or more elements or displays (for example an indicator of an        operational state or a power indicator) of the substrate, this        source in particular being located plumb with the substrate in        order to form a display by projection, or under the substrate in        order to form a display by transmission through the substrate;        and    -   at least one interface for communicating with at least one        element of the worktop (for example with the one or more light        sources and/or the one or more heating elements), and/or if        needs be wirelessly with at least one external element (exterior        to the worktop), for example with an external module (an        external system, an external device).

The product according to the invention meets the stated aim, the presentinvention thus providing a novel interactive item of furniture and/orappliance (especially allowing functions such as a cooking function tobe activated and zones or data to be displayed) that is suitable for useboth in a kitchen and in other habitable rooms, the worktop possiblyforming part of an optionally unapertured unit, a table, a counter,etc., this worktop being mounted or being able to be mountedhorizontally on (in particular on top of) one or more supportingelements (carcass of a unit, supporting leg(s)) in order to provide astable surface intended for various uses, the worktop, item of furnitureor appliance according to the invention having a continuous top surfacethat allows, simultaneously or in succession, objects (such as pieces ofpaper, computers, vases, tableware, etc.) to be held, activities (suchas work, games, reading, etc.) to be carried out and food to be preparedcooked or heated in appropriate containers.

More generally, the invention also relates to a worktop formed from atleast one substrate made of a transparent monolithic glazing materialand of area larger than 0.7 m², equipped with a coating so that thesubstrate equipped with the coating has a haze higher than 15%, a lighttransmission T_(L) lower than 60% and an opacity indicator higher than85, this worktop being intended to form part of a multiuse interactiveitem of furniture or appliance (intended for a number of uses such aslisted in the preceding paragraph), in particular such as defined aboveaccording to the invention.

The invention also relates to the use of a substrate, and in particularof a plate, made of a monolithic transparent glazing material and ofarea larger than 0.7 m², equipped with a coating so that the substrateequipped with the coating has a haze higher than 15%, a lighttransmission T_(L) lower than 60% and an opacity indicator higher than85; as a multiuse interactive worktop, in particular such as mentionedin the above paragraphs.

As indicated above, the worktop is formed from a large substrate orplate made of a monolithic glazing material (the glazing materialforming a single object/being a single part, even though the substratemay if needs be contain voids, generally produced in the part after ithas been formed, for esthetic or functional reasons) the advantage ofsuch a large monolithic plate especially being that it provides a mostlycontinuous/uniform/joint-free surface that is attractive, easy to clean,more ergonomic and safer (as it is made of an impermeable material, incase of the spillage of liquids, etc.), etc. The substrate essentiallyor only consists of the glazing material, this substrate/glazingmaterial possibly if needs be being equipped with thin decorative orfunctional coatings (especially of the order of a few tens of nanometersto a few hundred microns or more in thickness), for example made of anenamel, paint, thin films, etc. as specified below.

Contrary to common practice in the field of glass-ceramics inparticular, this (substrate made of a) glazing material is large insize, its area (corresponding to the product of its length by its widthfor its largest face—generally its upper face, which is intended to bevisible and to hold (household, cooking-related and/or work-related)articles being larger than 0.7 m², preferably larger than 0.9 m²,especially larger than 1 m² and in particular larger than or equal to 2m². However, in the case of glass-ceramics in particular, themanufacture of large plates leads to many problems with flatness andhandling. In the present invention, a large plate that nonetheless has agood flatness may nevertheless advantageously be obtained by decreasingrun speed (or increasing the length of the ceramitization furnace orincreasing dwell time in the furnace) relative to the (standard) speed(or length of the furnace or time) conventionally used to obtainglass-ceramic plates of conventional size smaller than 0.4 m², asexplained below with regard to the process according to the invention.

The substrate/glazing material according to the invention isadvantageously flat (or mostly or almost flat) and in particular has aflatness (height between the highest point and the lowest point of thesubstrate relative to the mean plane of the substrate, excluding anydeformations intentionally produced in the substrate for esthetic orfunctional purposes) lower than 0.1% of the diagonal of the substrate,and preferably lower than 3 mm, especially lower than 2 mm and inparticular lower than 1 mm or even of about zero, depending on thesize/area/diagonal of the substrate, the flatness being measured using aSurFlat ondulometer sold by Visual. The substrate is generally ofgeometric shape and in particular rectangular or even square, circularor oval, etc., and generally has an “upper” face (face that is visible)in the use position and a “lower” face (generally hidden, in the body orcarcass of the unit incorporating the worktop) in the use position, andan edge face (or edge or thickness). The upper face is generally flatand smooth but may also contain at least one protruding zone and/or atleast one recessed zone and/or at least one aperture and/or have bevelededges (these features being added during manufacture of the substrate,for example by rolling, gravity bending or pressing, etc., or beingadded during reworking of the substrate), etc., these variations inshape advantageously forming continuous variations in the plate (i.e.they do not involve other materials or joints). The lower face mayespecially be smooth or equipped with studs increasing its mechanicalstrength and obtained for example by rolling.

The thickness of the monolithic substrate made of the monolithic glazingmaterial that is used is generally at least 2 mm, especially at least2.5 mm, and in particular about 3 to 30 mm, said thicknessadvantageously being smaller than 15 mm, in particular about 3 to 15 mmand especially from 3 to 10 mm.

The glazing material of the substrate used is advantageously resistantto high temperatures and/or has an expansion coefficient of zero oralmost zero (for example of lower than 15×10⁻⁷ K⁻¹) and in particular isadvantageously a glass-ceramic or toughened (especially chemically orthermally tempered) glass. Preferably, the substrate is a substrate madeof glass-ceramic. As defined according to the invention, the glazingmaterial is advantageously transparent and in particular has a lighttransmission T_(L) such as defined according to the invention higherthan 60% and especially higher than 80%.

The glass-ceramic used may especially have a composition such asdescribed in the patent applications published under the followingnumbers: WO2013171288, US2010167903, WO2008065166, EP2086895,JP2010510951, EP2086896, WO2008065167, US2010099546, JP2010510952,EP0437228, this glass-ceramic in particular being a lithiumaluminosilicate glass-ceramic.

The glass-ceramic may be arsenic-fined (i.e. be (made from a motherglass)) of composition comprising about 0.2% to 1.5% by weight arsenicoxide (expressed as As₂O₃), or may not be arsenic-fined (in particularhaving an arsenic oxide content of 0.2% and in particular lower than0.1% or even zero)/be tin-fined.

The glazing material may also be a non-ceramitized tempered glass, forexample a bulk-colored tempered lithium aluminosilicate glass such asdescribed in the patent applications published under the followingnumbers: FR1060677 and WO2012080672, or even a tempered glass of anothertype (soda-lime, borosilicate, etc.) for example such as described inthe patent application published under number WO2012146860.

The glass-ceramic or the tempered glass are obtained by respective sprocesses described in the aforementioned documents using treatmenttemperatures and cycles allowing the glazing material having theselected properties given in the definition of the invention to beobtained. In the case of glass-ceramics, these processes are preferablymodified by decreasing run speed by at least 25% and preferably by atleast 50%, or by increasing the length of the ceramitization furnace orthe dwell time in said furnace by at least 25% and preferably at least50%, relative to the speeds, lengths and times, respectively, normallyused to obtain a large flat substrate such as required according to theinvention, as explained below.

The transparent glass-ceramic substrate generally comprises crystals ofβ-quartz structure within a residual vitreous phase, the absolute valueof its expansion coefficient advantageously being lower than or equal to15×10⁻⁷/° C., or even to 5×10⁻⁷/° C., this glass-ceramic for examplebeing that of the plates sold under the name KeraLite by EuroKera.

The glazing material may if needs be also comprise colorants givingparticular hues to the substrate, for example vanadium oxide, ironoxide, cobalt oxide, cerium oxide, selenium oxide, chromium oxide, oreven nickel oxide, copper oxide and/or manganese oxide, etc.

As indicated in the definition of the invention, the substrate/glazingmaterial is provided with a coating in order for the assembly to havethe properties defined in the invention, this coating especially servingas a masking means intended to mask at least some of the subjacentelements (the heating means in particular), and if needs be allowing anopacity/low transmission and/or a haze favorable to the formation of adisplay by transmission of light through the substrate, or to theformation of a display by projection of light onto the surface of thesubstrate, which then forms a screen, to be obtained, as will beexplained below.

The coating advantageously takes the form of at least one coat of paintor layer of thin films on at least some or most or even all of the lowerface of the glazing material, in particular a coat of paint of about 5to 500 μm in thickness and especially 5 to 50 μm in thickness. The paintused is preferably able to withstand temperatures higher than 350° C.(and generally comprised between 350° C. and 500° C.) and is for examplebased on silicone resin(s) and in particular silicone alkyd resin(s)(i.e. silicone resin(s) modified by the incorporation of alkyd resin(s))or may even be based on other resins, such as epoxy or polyurethaneresins, if intended for use at low temperatures below 200° C., thispaint possibly, if needs be, comprising pigments and preferably enamelpigments (in proportions not exceeding 50% by weight) depending on thedesired color. Alternatively, this coating may also take the form of atleast one enamel layer on the upper face of the glazing material. Thesubstrate thus coated may for example be of the same type as the platessold under the name KeraResin by EuroKera.

As defined according to the invention, the coated substrate forming theworktop is selected so as to have a haze higher than 15% and inparticular higher than 40% or even higher than 60%, a light transmissionT_(L) lower than 60% and in particular lower than 50% or even lower than30% (this light transmission especially being nonzero/higher than 0) andan opacity indicator higher than 85 and preferably higher than 90 (andin particular lower than 100). The substrate has these properties overmost (in particular over at least 80% or even over 100%) of its area,excluding any possible additional localized decorations (for examplemade of an enamel) or localized components applied to its surface.

Haze measures the extent to which light is scattered and is defined, inthe context of the invention, as being the ratio of diffuse transmissionto the total transmission at a wavelength equal to 550 nm, this hazebeing evaluated for example using the spectrophotometer equipped with anintegrating sphere used for the light transmission measurements.

The light transmission T_(L) is measured according to standard ISO9050:2003 under illuminant D65, and is the total transmission(integrated in the visible domain), taking into account both directtransmission and possible diffuse transmission, the measurement beingcarried out for example using a spectrophotometer equipped with anintegrating sphere, the measurement at a given thickness then beingconverted if needs be to the reference thickness of 4 mm according tostandard ISO 9050:2003.

The opacity indicator (or factor or coefficient) Ω is determined in thepresent invention by the formula Ω=100−ΔE* and is evaluated by measuring(color in reflection obtained using a Byk-Gardner Color Guide 45/0colorimeter) the color variation ΔE*, corresponding to the differencebetween the color, measured in reflection on the upper face of thesubstrate, of the substrate placed on an opaque black background, andthat of the substrate placed on an opaque white background(ΔE*=((L_(N)*−L_(B)*)²+(a_(N)*−a_(B)*)²+(b_(N)*−b_(B)*)²)^(1/2),according to the formula established by the CIE in 1976, L_(B)*, a_(B)*,b_(B)* being the color coordinates of the first measurement on the whitebackground and L_(N)*, a_(N)*, b_(N)* being those of the secondmeasurement on the black background in the CIE 1976 color space.

The coated substrate according to the invention allows, if needs be, adisplay to be formed by projection, as will be explained below, inparticular in combination with light sources placed thereabove, andallows luminous zones to be displayed in order especially to signal thecooking zones when they are turned on, and/or allows if needs be adisplay to be formed by transmission of light using sources placedthereunder, this substrate masking at the same time elements (such asthe heating elements and cables) placed underneath.

As defined above, the article according to the invention also comprisesat least one heating element (or heater element), for example one ormore radiant or halogen elements or one or more gas burners and/or oneor more inductive heating means, these heating means generally beinglocated under the worktop and hidden by the latter when turned off. Theworktop of the article according to the invention may comprise one ormore heating elements and likewise one or more rings. The term “ring” isunderstood to mean a cooking location. The article according to theinvention may comprise a plurality of types of heating element or ring(gas ring, radiant ring, halogen element or inductive element).Preferably, the article according to the invention comprises by way ofheating element(s) one or more inductive heating means.

The one or more heating means may be located in a defined zone (forexample at one end of the substrate) or a plurality of zones of thesubstrate, or may be uniformly distributed under the substrate, forexample occupying at least 25% of the area of the substrate, or may evenoccupy an area almost equivalent to that of the substrate (for examplemore than 50%, especially more than 75% or even more than 85%, or even100% of the main area of the substrate), a plurality of small inductorsfor example lining the substrate under its lower face, in order to allowany zone to be heated as needs be.

The cooking locations on the worktop, plumb with the heating means, maybe signaled (or not, in the case for example of a worktop equipped withheating means covering the entirety of its areal extent), on activationand/or permanently, especially by means, respectively, of one or morelight sources and/or by means of a permanent decoration, for examplemade of an enamel. The patterns allowing the cooking zones to besignaled (and likewise any patterns signaling other zones or functions)may be relatively large in size, for example it may be a question ofcircles each of which encircles a heating element, or of small patterns(triangles, crosses, etc.) at the center or bottom thereof, etc.

Preferably, the cooking locations (and/or if needs be other zones and/orelements and/or functions and/or decorations) are signaled by at leastone light source such as mentioned in the definition of the invention,this source once activated indicating for example the location using aluminous pattern (especially a disk, circle, cross, triangle, etc.) offixed or variable color and/or size. Alternatively, is they may beindicated permanently, via a permanent pattern (especially a roundcircle, a cross, a triangle, etc.), especially obtained by depositingone or more layers (in particular such as those used to decorateglass-ceramics), for example made of enamel, on the surface of the plate(especially on the upper face).

In one preferred embodiment, and especially when the coated substrate isopaque or has a very low light transmission (especially lower than 5%),the one or more cooking locations (and/or if needs be other zones and/orelements and/or functions and/or decorations) are signaled by, and/orrevealed using or by means of, at least one light source such asmentioned in the definition of the invention, on activation of saidsource, said source being located above (in the use position) or on thesame side as the visible face of the substrate (i.e. on the side onwhich the display is to be formed or from which it is intended to beviewed) and allowing a luminous display to be formed by (direct)projection onto this surface/face, which then forms a screen. Thesubstrate defined according to the invention is particularly well-suitedto this type of display.

In another embodiment, for a coated substrate having a lighttransmission T_(L) of at least 5%, the one or more cooking locations(and/or if needs be other zones and/or elements and/or functions and/ordecorations) may (also or alternatively) be signaled by and/or revealedusing or by means of at least one light source such as mentioned in thedefinition of the invention, on activation of said source, said sourcebeing placed under the substrate (in the use position) and being hiddenthereby when turned off, said source allowing a luminous display to beformed via transmission through the worktop.

One or more light sources may also allow other elements or functions tobe displayed, for example control zones or means (taking the form oftouch controls, logos or even keyboards, etc.) or indicators (ofcurrents/power, time, etc.) may be displayed, these for example beingactivatable via contact with the surface of the worktop (sensors locatedunder the surface for example being used to detect this contact) orremotely (especially via wireless communication), or even by a simplemovement of the hand (via sensors or detectors located if needs be onthe exterior and sensing the movement, for example by triangulation, inorder to convert it, especially using an algorithm and a suitableinterface, into the activation of a function for example), or if needsbe by placing a given object (saucepan, etc.) in a given location (suchas a cooking zone) on the plate. The one or more light is sources mayalso allow decorations or various data (display for example of computerpages, culinary recipes, etc.) downloaded for example via a wirelesslink using an appropriate interface to be displayed, said data beingprojected or transmitted from the light sources onto the surface of theplate.

If needs be, the article according to the invention may comprise aplurality of light sources, for illuminating a plurality of zones or fordisplaying complex decorations or texts, or in order to increase theuniformity of the illumination, these sources possibly being placedalong different axes and at different illumination angles in order toobtain the desired effect, without reflections or undesirable shadowing.In particular in the case of illumination via projection onto theworktop, which then acts as a screen, a plurality of sources are forexample placed so that the angle between each source (or between eachelement, mirrors for example, transmitting the light toward the worktop)and the normal to the worktop is comprised between 5 and 60° andpreferably between 30 and 45° in order to minimize the effects ofshadows projected by a person using the worktop.

The one or more light sources may advantageously be formed bylight-emitting diodes, especially for reasons of bulk, efficacy,lifetime and resistance to environmental conditions (heat, etc.), and/ormay be other types of sources, for example halogen or incandescentlamps, lasers or liquid-crystal screens, the sources possibly, if needsbe, being used in combination with lenses or mirrors, etc.

The diodes are advantageously semiconductor chips made of mineralmaterials (LEDs) especially emitting in one direction, and may beencapsulated, i.e. comprise a semiconductor component and a package (forexample made of an epoxy or nylon resin) encapsulating the semiconductorcomponent. These diodes may also be semiconductor chips withoutcollimating lenses, for example of about one hundred pm or one mm insize, optionally with a minimal (for example protective) encapsulation.

The diodes may, if needs be, be borne by a carrier or strip or base,this base possibly having a (flat or inclined) surface that has beentreated and/or made reflective for a better luminous efficacy, thissurface for example being coated with a lacquer or coat of paint and/ora mirror coating, and/or coupled to a white or metal reflector in orderto better direct the radiation emitted.

If needs be, it is also possible to use organic light-emitting diodes(OLEDs) especially consisting of a superposition of organicsemiconductor layers between electrodes, and producing various colors towithin one pixel following the path taken by the electricity through theorganic layers.

Each source or the sources are joined (to the substrate or to asupporting member, for example to a part of the item of furniture and/orappliance or to an external part (associated with said item of furnitureand/or appliance) such as a rail or a device suspended above the worktop(this device possibly also including other components such as a hood,the one or more sources possibly especially being integrated into thishood)), by soldering, clip fastening, adhesive bonding, etc., if needsbe by way of another element; for example, it is possible to mountdiodes, soldered to a carrier itself housed at the bottom of a metalprofile, by clip fastening or adhesive bonding of the profile. Thepositions of the one or more sources (relative to the plate inparticular) are adapted to allow a display to be formed on the substrate(by projection (especially from above) onto the plate (which then actsas a screen) or through the glass-ceramic when the substrate is notcompletely opaque).

The sources, and their power supplies and actuating mechanisms, mayoptionally be disassociated in order to allow desired zones ofillumination to be illuminated simultaneously or individually dependingon the need. Each source may be monochromatic (pure color) orpolychromatic (mixed color).

The expression “monochromatic light source” is understood to mean alight source having a single emission peak in the visible wavelengthrange and such that the width of the peak varies from 1 to 100 nm andpreferably from 5 to 50 nm.

The expression “polychromatic light source” is understood to mean alight source that has at least two emission peaks at differentwavelengths in the visible wavelength range. The color perceived (by theretina) is then the result of mixing of the various wavelengths. It maybe a question of an LED and/or an LED display having an emissionspectrum containing a main emission peak and another emission peak thatis wider than the main peak and generally of lower intensity, this peakfor example being due to fluorescence. The polychromatic LED inparticular emits a first emission (of high or low intensity) comprisedbetween 400 and 500 nm and a second emission (of high or low intensity)in the visible beyond 500 nm (case for example of LEDs formed from atleast one light-emitting crystal and of one or more photoluminescentphosphors). It is especially possible to use, by way of sources, whiteLEDs, LEDs that emit polychromatic light, formed for example from threemonochromatic sources of independently adjusted intensities and of the“RGB” type (with three sources: a red source, a green source and a bluesource), etc.

One or more sources may also be integrated into or coupled to orcombined with one or more display-type structures (“7-segment”light-emitting diode or liquid-crystal displays for example) and/ortouch-sensitive electronic control screens or panels with digitaldisplays (if needs be over a wireless link via an interface), orintegrated into another device such as an extractor hood as indicatedabove, etc.

Apart from the one or more sources, the article according to theinvention may also comprise at least one waveguide intended to propagatelight from one part of the article to another (in particular by totalinternal reflection or by reflection from metallic surfaces) if need bewhen the sources are placed under the worktop, each light source thenbeing attached to the guide in question and interacting therewith byemitting its light into it so that the guide then transmits said light,the one or more light sources for example emitting into/being coupled tothe edge face or edge of the guide. This guide is advantageously clearor transparent, and may be added (assembled after having been designedseparately) for example under the lower face of the plate. It may beorganic and/or plastic (for example made of polycarbonate or polymethylmethacrylate PMMA) or mineral (for example it may be made of glass). Thearticle according to the invention may comprise a plurality s of guideseach dedicated to one or more zones of illumination, or a unitary guideprovided, if needs be, with apertures. The guide may be joined directlyto the substrate or to another part of the item of furniture and/orappliance or to a supporting member, and may for example be securelyfastened to the carcass on which the worktop rests. The guide allows,inter alia, the light to be better conveyed to the desired zones ofillumination.

Especially in the case where one or more sources, associated if needs bewith at least one waveguide, are placed under the worktop, the item offurniture and/or appliance may also comprise, in the illuminated zone,at least one means for extracting the radiation emitted by the one ormore sources, for example one or more scattering elements or treatments,in particular a layer added to the surface and/or any treatment ordifferential texturing of the surface (either locally or to/of theentire surface) of the waveguide or the extraction surface, such asobtained by laser etching, printing an enamel, chemical (acid, etc.)etching or mechanical attack (sandblasting, etc.), etc. An extractionsurface may, if needs be, be provided in the thickness of the guide, forexample by applying a laser etching technology to its interior. Thegeometry and the roughness of the edge of a waveguide may also bemodified in order to allow light to be locally and controllablyextracted. The one or more extraction means allow the radiation to beextracted from the guide toward the zone that it is desired toilluminate. They may, if needs be, be combined with another treatmentallowing the zones to be illuminated to be targeted, for example ascreen-printed mask (masking certain zones and preventing the passage oflight) deposited on part of one face of the substrate.

If needs be, the item of furniture and/or appliance may also comprise atleast one filter (coupled (in operation) to at least one source, so asto form a colored luminous zone of a chosen color, this filter beinggenerally positioned between the source and the plate and possiblyespecially being combined (or securely fastened) to the source and/or toanother intermediate element and/or to the plate.

The term “filter” is understood to mean an optical filter (acting on thetransmission of the light) and in particular a color filter (the actionon the transmission of the wavelength being wavelength dependent), thisfilter in particular being a generally flat element or componentespecially taking the form of a film or layer or composite based on atleast one organic or mineral material that is (semi)transparent (in thesense especially that it is transparent at (a) certain wavelength(s) inthe visible and not transparent at/opaque at/affects one or moreother(s)), in particular allowing certain wavelengths in the visiblespectrum to be absorbed and/or reflected and/or reemitted. This filtermay especially be an absorption filter (the action on the transmissionof light occurring by absorption at certain wavelengths, the absorbedlight possibly especially being converted into heat and/or emitted atother wavelengths), or a reflective filter (the action on thetransmission of light occurring by reflection at certain wavelengths).The filter may be added (fabricated separately) and combined with atleast one light source and/or another intermediate element or theworktop, or it may be integrated into or produced directly on saidsource and/or said element and/or said worktop, for example in the formof a printed layer, for example printed by inkjet printing. Theradiation emitted by the source passes through the corrective filter inorder to produce the required display on or through the substrate withwhich this assembly is combined. The filter may allow various colors,for example at least one colored zone of white color, or of a mixedcolor obtained by mixing a plurality of wavelengths, to be formed.

The item of furniture and/or appliance according to the invention,depending on the sources used (and, if need be, the filters used) andtheir locations may comprise one or more luminous/display zones having afunctional and/or decorative purpose, said one or more zones possiblybeing in any zone of the plate (including heated zones), and it ispossible to provide a plurality of luminous/display zones that aredifferent (different color, brightness) and/or each zone may itself bevarious colors.

As indicated above, the item of furniture and/or appliance according tothe invention also comprises at least one interface for communicatingwith at least one element of the worktop (such as the one or more lightsources and/or the one or more heating elements) and/or, for examplewirelessly, with an element external to the worktop.

This (especially machine-machine or human-machine) communicationinterface may be a device especially allowing the heating elementsand/or light sources to be controlled or commands to be transmittedthereto from or via control knobs or touch controls integrated into theworktop or separate therefrom and located on an external element that isadvantageously immovable or movable, in the case especially where thecommands are communicated wirelessly.

Preferably, the interface enables wireless communication with a systemexternal to the worktop (this system possibly forming part of the itemof furniture and/or appliance according to the invention and possiblyitself forming an interface), for example allowing heating zones and/orlight sources to be activated and/or various functions (increase ordecrease of power, cooking time, display of data on the worktop, etc.)to be controlled remotely, the commands given via the external systembeing transmitted via the interface to the relevant components of theitem of furniture and/or appliance. The interface may also be a controlinterface located on the worktop (control panel) and that transmits thecommands by wire or optionally wirelessly to other components of theworktop or to other components external to the worktop (for example toremote sources when the illumination is projected).

The external system in the case of remote control may for example takethe form of a keyboard, a tablet or a touch screen or of a cellphone,this system possibly being fixedly mounted (for example fastened to awall) or movable. This embodiment especially has the advantage ofpreventing finger marks on the worktop or cooking zones (which areunattractive and easily seen on glazing materials). Remote activation ofthe controls also makes it possible to decrease the risk of the operatorbeing burnt as there is no need to interact with controls located inproximity to the cooking zones. Especially for the sake of safety, thewireless link may advantageously be of limited range (for example ofrange limited to the volume of the room in which the item of furnitureand/or appliance is located) and/or be equipped with safety features inorder to prevent inadvertent activation by a person outside of the room.The wireless communication in particular is achieved via electromagneticor radioelectric waves, if needs be using systems of Bluetooth, WLAN,Wi-Fi, etc. type.

The interface may allow various signals initiated via contact or evenvia a movement to be transmitted in order to activate various componentsas mentioned above (for example it may convert a movement, detected bysensors by triangulation, these sensors being connected to thisinterface (and if needs be forming part thereof), into the activation ofa function (for example the increase of the heating power, theillumination of the heated zones, etc.). It may also allow various data(such as Internet pages, wallpapers, culinary recipes, etc.) to bedownloaded and/or transmitted, these data for example being transmittedto light sources in particular allowing them to be displayed on thesurface of the worktop.

At least one interface is generally located on or under the worktop orin proximity thereto. The item of furniture and/or appliance accordingto the invention may also comprise a plurality of interfaces, of thesame type or of different types, for example allowing various elementsto be activated, or the item of furniture and/or appliance may comprisea plurality of interfaces that, if needs be, operate differently (are ofdifferent design, operate at different frequencies, etc.) forcontrolling a given element (for example a heated zone) with a higherlevel of safety. If needs be, provision may especially be made for aninterface allowing the activation of the heated zones to be coordinatedwith the activation of the light sources. The interface may be formed byone or more sensors, connectors, control elements or any other electric,electronic or electromagnetic component, etc.

Preferably, the item of furniture and/or appliance according to theinvention comprises at least one interface for communicating wirelesslywith at least one external element for activating various zones and/orfunctions of the substrate, in particular when the light transmissionT_(L) of the substrate is low.

Apart from the interface, the item of furniture and/or appliance orworktop may be equipped with various cables, connectors or other,especially electrical, elements contributing to the transmission ofcommands from one part of the item of furniture and/or appliance toanother.

The item of furniture and/or appliance and in particular the worktopaccording to the invention may also comprise various functional and/ordecorative coatings, especially chosen from those generally used withthe glazing materials in question, for example coatings based on enamel,paint, one or more thin (for example metal, dielectric, etc.) films,etc. For example, one of the faces of the substrate may comprise one ormore enamel layers or one or more enamel patterns having a decorativerole and/or that are used to signal one or more elements (displays,cooking zones, etc.) and/or that act as a coloring layer or a maskand/or that are used for other purposes (as light extractors or toincrease the illumination uniformity, eta). In particular, the worktopmay be equipped with a functional layer that provides it with one ormore additional properties, for example an anti-scratch coating or alayer that increases its mechanical strength, etc. The coating may forexample be formed using processes such as screen printing, cathodesputtering, inkjet of enamel printing, etc., the coating possibly,depending on the type of coating and the desired function, especiallybeing applied to the visible face or to the opposite face. For example,in the case of an enamel decoration, the latter is preferably depositedon the upper face especially for reasons of visibility, whereas anopacifying layer (such as the coating mentioned according to theinvention) is preferably deposited on the opposite face, i.e. the facethat is not intended to be visible, especially to better protect it fromabrasion, etc.

As indicated above, the decorations (or at least some thereof) ordisplays of the worktop may also be obtained, with some advantage, via aluminous display (as opposed to by deposition of a coating), inparticular by projecting light onto the worktop, which then forms ascreen, as already mentioned above.

The present invention also relates to a process for manufacturing anitem of furniture and/or appliance according to the invention and inparticular the worktop of said item of furniture and/or appliance whensaid worktop is formed from at least one glass-ceramic substrate of arealarger than 0.7 m², in which at least one cycle of ceramitization of aglass plate of area larger than 0.7 m² is carried out in order to obtainsaid substrate, and in which run speed is decreased by at least 25% andpreferably by at least 50%, or the length of the ceramitization furnaceor the dwell time in said furnace is increased by at least 25% andpreferably at least 50%, relative to the optimal or conventional speed,length or dwell time, respectively, used to obtain a glass-ceramicsubstrate of area smaller than 0.4 m².

It will be recalled that glass-ceramic plates are generally manufacturedas follows: glass of the composition selected for forming theglass-ceramic is melted in a melting furnace, then the molten glass isrolled into a standard ribbon or sheet by passing the molten glassbetween rollers, and the glass ribbon is cut to the desired size. Theplates thus cut are then ceramitized in a way known per se, theceramitization consisting in baking the plates with a temperatureprofile selected to convert the glass into the polycrystalline materialreferred to as “glass-ceramic”, the expansion coefficient of which iszero or almost zero and which is able to withstand thermal shocks of asmuch as 700° C. The ceramitization generally comprises a step ofgradually increasing temperature to the nucleation range, s generallylying near the glass transformation range; a step, lasting severalminutes, in which temperature is increased through the nucleation range;a new progressive increase in the temperature up to the temperature ofthe ceramitization stage; holding the temperature of the ceramitizationstage for several minutes; and then rapid cooling down to roomtemperature. If needs be, the process also comprises a cutting operation(generally before the ceramitization) for example with a water jet, orinvolving mechanical scoring with a cutter, etc. followed by a shapingoperation (molding, beveling, etc.). The process may also comprise astep of rolling or gravity bending in order to form particularthree-dimensional shapes.

In the present invention, the glass-ceramic follows a ceramitizationcycle that gives it the desired properties, in particular a transparentappearance.

Other details and advantageous features will become more apparent belowfrom the description of a nonlimiting embodiment of the invention, givenwith reference to the appended drawings in which:

FIG. 1 shows a schematic perspective view of an item of furniture and/orappliance according to the invention;

FIG. 2 shows a schematic top view of a similar item of furniture and/orappliance (the utensils on the surface and the underlying unit elementsare not shown); and

FIG. 3 shows a schematic side view in which a side panel of the unit(23) has been removed in order to allow certain components of the itemof furniture and/or appliance to be seen.

In this example the item of furniture and/or appliance (1) according tothe invention comprises a unit (2) formed from a carcass (4) surmountedby a worktop (5) formed from at least one glass-ceramic substrate of 2m² area, formed from a transparent (monolithic) glass-ceramic plate (6)(the glass-ceramic intrinsically having a light transmission T_(L) of88%), this glass-ceramic plate being equipped with a coating (10) madeof paint of 42 μm thickness based on silicone resins including blackpigments, this coated plate being of the same type as those sold underthe reference KeraResin by Eurokera, this plate having a smooth upperface and a smooth lower face (this face likewise possibly being providedwith studs), and a thickness of 4 mm, the coated substrate having a hazeof 66.7%, a light transmission T_(L) of 0.03% and an opacity indicatorof 99.96. This substrate is for example obtained by decreasing, in theprocess for manufacturing glass-ceramics of the KeraResin type, the runspeed through the ceramitization furnace by 50%.

The glass-ceramic substrate obtained has a flatness of less than 2 mm(the flatness obtained being between 2 and 3 mm for a speed decreased byonly 25%, and being more than 15 mm for a speed that is unchangedrelative to that used in the aforementioned application to obtain aplate of standard size smaller than 0.4 m²), the flatness required toobtain good optical properties and good coupling and thermal efficiencyproperties in particular being lower than 3 mm and preferably lower than2 mm.

The item of furniture and/or appliance furthermore comprises in thepresent example three heating elements (7), inductors for example,placed under the plate (6). These inductors are in the present casearranged in the middle of the worktop, but they could equally well belocated at one end of the worktop.

The item of furniture and/or appliance also comprises three lightsources (8) intended to signal the cooking locations and placed abovethe substrate (plumb above the worktop). These sources allow the cookinglocations to be signaled, for example by way of a disk or a circle ofcolored light (9) delimiting each location (the colors possibly if needsbe being identical or different for each location) and encircling theinductors, when these sources are activated, or even when the heatingelements are activated if the sources are connected to said elements viaan appropriate interface. The sources (8) are for example formed by aplurality of LEDs borne by a base housed in a profile, and for exampleintegrated into an extractor hood (14) located plumb above the worktop.These sources, apart from signaling heating zones, may also oralternatively serve to illuminate (locally or entirely) the worktop, orto display by projection various items of information, such as data tobe displayed, culinary recipes (11), etc.

The item of furniture and/or appliance furthermore comprises at leastone interface (12) (hidden by the substrate) for communicating with theheating elements, and, if needs be, with the light sources, thisinterface also communicating wirelessly with an external system forexample taking the form of a touch-sensitive tablet (13) for controllingthe activation of various zones or functions of the plate or item offurniture and/or appliance. The external system may advantageously bemovable and be kept on the worktop (FIG. 1) or be used to remotelyactivate (FIG. 3) various zones or functions. Alternatively orcumulatively, the interface could also comprise or be connected to anintegrated control panel, located on the surface of the substrate (2),for controlling the activation of various zones and functions, inparticular of the substrate.

The item of furniture and/or appliance also comprises other elements,especially electrical cables (15) for the activation of the heatingelements and for the activation of the sources, and comprises drawers(15) or cupboards (17) arranged in the carcass supporting the worktop,for storing various articles, etc. The item of furniture and/orappliance may also comprise other elements, for example the worktop maycomprise a trim and the substrate may be coated with an optionallylocalized permanent decoration, an enamel decoration for example. Thecarcass may be unapertured or comprise various voids (such as the void(18)), or incorporate other elements (for example a built-in oven,etc.). The worktop (5) may be used for various purposes, such as forwriting (as symbolized by the paper and pen (19)), to hold objects (assymbolized by the tableware (20)) while also allowing food to be cooked(as symbolized by the cooking recipients (21)), etc. If needs be, thecarcass may also be replaced by supporting legs (for example only thepanels 22 and 23, or four legs at the four corners, components locatedunder the worktop in this case preferably being hidden by a localizedhousing of a few centimeters thickness, under the substrate) like thoseof a table.

The item of furniture and/or appliance according to the invention mayespecially and advantageously be used to create a new range ofinteractive and multiuse units especially integrating cooking zones or acooking function.

1-20. (canceled)
 21. An item of furniture or appliance, comprising: atleast one worktop formed from at least one substrate made of atransparent monolithic glazing material and of area larger than 0.7 m²,equipped with a coating so that the substrate equipped with the coatinghas a haze higher than 15%, a light transmission T_(L) lower than 60%and an opacity indicator higher than 85; at least one heating element;at least one light source configured to light up one or more zones orone or more elements or displays of the substrate, the source beinglocated plumb with the substrate in order to form a display byprojection, or under the substrate in order to form a display bytransmission through the substrate; and at least one interface forcommunicating with at least one element of the worktop.
 22. The item offurniture or appliance as claimed in claim 21, wherein the area of thesubstrate made of a glazing material is larger than 0.9 m² and athickness of said substrate is at least 2 mm and smaller than 15 mm. 23.The item of furniture or appliance as claimed in claim 21, wherein thesubstrate has a flatness lower than 0.1% of a diagonal of the substrate.24. The item of furniture or appliance as claimed in claim 21, whereinthe substrate is made of tempered glass or glass-ceramic.
 25. The itemof furniture or appliance as claimed in claim 21, wherein the glazingmaterial has a light transmission T_(L) higher than 60% and thesubstrate made of the glazing material equipped with the coating has ahaze higher than 40%, a light transmission T_(L) lower than 30% and anopacity indicator higher than
 90. 26. The item of furniture or applianceas claimed in claim 21, wherein the glazing material contains colorants.27. The item of furniture or appliance as claimed in claim 21, whereinthe at least one heating element includes one or more inductive heatingmeans, the one or more inductive heating means being located in one ormore zones of the substrate or being uniformly distributed under thesubstrate occupying at least 25% of the area of the substrate.
 28. Theitem of furniture or appliance as claimed in claim 27, wherein at leastone of cooking locations on the worktop, plumb with the heating means,other zones, elements, functions, and decorations are signaled, onactivation or permanently, by one or more light sources or by apermanent decoration.
 29. The item of furniture or appliance as claimedin claim 28, wherein the at least one of the cooking locations, otherzones, elements, functions, and decorations are signaled or revealed orby the at least one light source, on activation of said source, saidsource being placed above the substrate or on a same side as a visibleface of the substrate, and allowing a luminous display to be formed viaprojection onto the face, which then forms a screen, said source beingplaced under the substrate and allowing a luminous display to be formedvia the transmission of light through the worktop.
 30. The item offurniture or appliance as claimed in claim 28, wherein the coatedsubstrate has a light transmission T_(L) of at least 5%, and the atleast one of the cooking locations, other zones, elements, functions,and decorations are signaled or revealed by the at least one lightsource, on activation of said source, said source being placed under thesubstrate and being hidden thereby when turned off, said source allowinga luminous display to be formed via transmission through the worktop.31. The item of furniture or appliance as claimed in claim 21, whereinthe at least one light source is activatable via at least one of contactwith a surface of the worktop, with the interface, with an externalsystem, and via a movement.
 32. The item of furniture or appliance asclaimed in claim 21, wherein the item of furniture or appliancecomprises a plurality of light sources that are placed so that the anglebetween each source, or between each element transmitting the light tothe worktop, and the normal to the worktop is between 5 and 60° in orderto minimize effects of shadows projected by a person using the worktop.33. The item of furniture or appliance as claimed in claim 21, whereinthe interface enables wireless communication with a system external tothe worktop to allow heating zones or light sources to be activated orvarious functions to be controlled remotely, the external systemincluding a keyboard, a tablet, a touch screen, or a cellphone, and thewireless communication being of limited range.
 34. The item of furnitureor appliance as claimed in claim 21, wherein the interface allowsvarious signals initiated via contact or a movement to be transmitted inorder to activate various components or allow data to be downloaded ortransmitted, the data being transmitted to light sources to be displayedon a surface of the worktop.
 35. The item of furniture or appliance asclaimed in claim 33, wherein the item of furniture or appliancecomprises one or more interfaces allowing the activation of the heatingzones to be coordinated with the activation of the light sources. 36.The item of furniture or appliance as claimed in claim 21, wherein theworktop comprises one or more functional or decorative coatings based onenamel, paint, or one or more thin films.
 37. The item of furniture orappliance as claimed in claim 21, wherein the worktop is mounted on oneor more supporting elements to form, with said supporting elements, atable, an unapertured unit, or a counter.
 38. The item of furniture orappliance as claimed in claim 21, wherein the at least one interface isconfigured to communicate wirelessly with at least one external element.39. A worktop, comprising: at least one substrate made of a transparentmonolithic glazing material and of area larger than 0.7 m², equippedwith a coating so that the substrate equipped with the coating has ahaze higher than 15%, a light transmission T_(L) lower than 60% and anopacity indicator higher than 85, the worktop being configured to formpart of the item of furniture or appliance as claimed in claim
 21. 40. Aprocess for manufacturing the item of furniture or appliance as claimedin claim 21, comprising: forming the worktop from at least oneglass-ceramic substrate of area larger than 0.7 m², the formingincluding carrying out at least one cycle of ceramitization of a glassplate of area larger than 0.7 m² in order to obtain said substrate, andin which run speed is decreased by at least 25% or a length of theceramitization furnace or dwell time in said furnace is increased by atleast 25% relative to an optimal or conventional speed, length or dwelltime, respectively, used to obtain a glass-ceramic substrate of areasmaller than 0.4 m².